Mixing machine



1965 G. w. ASHCRAFT 3,222,038

MIXING MACHINE Filed Aug. 9, 1963 2 Sheets-Sheet 1 INVENTOR George Wflshcmff United States Patent 3,222,038 MIXING MACHINE George W.Ashcraft, 5818 E. 12th St., Kansas City, Mo. Filed Aug. 9, 1963, Ser.No. 301,102 7 Claims. (Cl. 259-105) This invention relates to mixingmachines for use in the mixing of paint, the comminution of grain, andin various other applications where it is desired to mix a plurality ofsubstances or to reduce the particle size of a granulated product.

The ingredients of common paints include resins, pigments, solvents, anda vehicle or base. These constituents must be mixed together to form thefinished product. Such mixing involves considerably more than mereagitation of the various ingredients since the paint pigment usuallymust be dispersed in order to form a homogeneous solution or suspension.This is because the pigment is composed of minute particles which tendto form small agglomerates. Mixing breaks up the agglomerates anddisperses the particles throughout the solution.

Heretofore, ball mills have been employed to effect the desired mixingof these ingredients to form the finished paint. Although ball millshave proven satisfactory in mixing the various paint constituents toform a homogeneous solution or suspension, such mills often requireseveral days of operation before the ingredients therein become mixed todesired standards. Thus, the ball mill is relatively slow as comparedwith mixing apparatus in common usage in other fields.

Another type of mixing device employed heretofore in the mixing ofpaints uses an agitator to speed the formation of a homogeneous solutionor suspension. Such agitator-type mixers, however, are unfit for paintswhere dispersion of the pigment particles must be achieved in order toform the finished product.

It is, therefore, the primary object of this invention to provide mixingapparatus for use in the paint industry that will mix paint ingredientsto the desired standards in a shorter period of time than a ball milland will also effect dispersion of pigment or other particles.

It is another object of this invention to provide mixing and dispersingapparatus that impresses shear forces upon the products being mixed inorder to achieve mixing and dispersing thereof.

It is a further object of this invention to provide mixing apparatus asaforesaid having improved circulation of the products to be mixed toincrease the speed of mixing thereof.

Besides the mixing of paint, the instant invention is also suitable andcapable of effecting mixing and comminution of grains such as wheat,etc. Manifestly, the reduction of wheat and other grains to form flourand the like is undertaken on a wide scale. The instant in ventionprovides greater speed and efficiency in this operation than heretoforeobtainable with relative simplicity of structure.

Therefore, it is an important object of this invention to provideapparatus for reducing the particle size of wheat and other grains inthe formation of flour and the like.

Another important object of this invention is to provide mixingapparatus especially suitable for use with substances susceptible toshear forces for effecting reduction of particle size.

Still another object of this invention is to provide mixing apparatuswherein dispersion of agglomerated particles or comminution ofgranulated products is achieved without the use of engaging teeth ormoving parts subject to high stresses.

Yet another object of this invention is to provide mix- 3,222,038Patented Dec. 7. 1965 ice ing apparatus wherein the products to be mixedare heated by forces exerted thereon by the apparatus to thereby achieveimproved mixing.

Further objects will become apparent as the detailed descriptionproceeds.

In the drawings:

FIGURE 1 is a central, vertical sectional view of the apparatus with theinterior parts thereof including the drive shafts and the adjustablespacing mechanism shown in elevation for clarity;

FIG. 2 is a sectional view taken along line 22 of FIG. 1 with certaincomponents shown in elevation for clarity;

FIG. 3 is a plan view of the upper plate of the mixing apparatus;

FIG. 4 is a plan view of the middle or inner plate of the mixingapparatus;

FIG. 5 is a fragmentary view taken along line 55 of FIG. 1;

FIG. 6 is a fragmentary view taken along line 66 of FIG. 1;

FIG. 7 is a fragmentary, central, vertical sectional view of the lowerplate of the mixing apparatus and its associated retainer showing theinner drive shaft in elevation;

FIG. 8 is a detailed view along line 88 of FIG. 4; and

FIG. 9 is a vertical, sectional view through the housing of the geardrive mechanism showing the mechanical components of the mechanism inelevation.

Referring to the figures, the numeral 10 denotes a receptacle or tankemployed to receive the products to be mixed. Receptacle 10 has a top 12with an inlet 14 therein. Inlet 14 receives a cap 16 and permits theloading of products into receptacle 10 upon removal of the cap. Disposedwithin receptacle 10 and adjacent top 12 is a product deflector 17, thefunction of which will be fully described hereinafter. Deflector 17comprises an annular, outwardly convex surface formed by bending thesides of the receptacle inwardly to form a restriction 17'.

Receptacle 10 is provided with a bottom 18 having an outlet 20 thereinpermitting egress of products from the receptacle following the mixingoperation. A pipe 22 communicates outlet 20 with a valve 24, opening ofthe valve permitting such egress when desired by the opera tor of theapparatus.

Top 12 serves as a mounting platform for a U-shaped bracket 26. Bracket26 has a housing 28 of a gear drive mechanism 29 mounted thereon withtubular output shaft 30 of mechanism 29 extending through the bracketand into receptacle 10 through openings 31 in top 12. Mechanism 29 isoperably coupled with a prime mover 32 for effecting rotation of shaft30 in a manner to be fully described hereinafter. Prime mover 32 may bean electric motor.

An arm 34 is hingedly attached at 36 to one edge of top 12, the otherend of the arm terminating in a fork '38. Fork 38 receives a pair ofopposed pins 40 (as is evident in FIG. 6), the pins extending from andbeing rigid with a ring 42. Ring 42 is internally threaded to mate withthe external threads of a screw 44.

Screw 44 is mounted on top 12 at 46, such mounting at 46 permitting bothrotation of screw 44 and swinging movement thereof in a vertical planethrough arm 64. The upper end of the screw is rigidly secured to a crank48 permitting manual turning of the screw by the operator of theapparatus.

It may be seen, especially in FIGS. 1 and 5, that arm 34 is providedwith an eye 50 which has disposed there- Within a bearing assembly 52.Bearing assembly 52 comprises an outer race 54 having opposed pins 56extending therefrom and an inner race 58. Pins 56 are slidably receivedby corresponding slots 60 in eye 50. The inner race 58 of bearingassembly 52 surrounds and is rigid with shaft 30, thereby preventinglongitudinal shifting of shaft 30 while arm 34 is stationary.

In FIGS. and 9 it may be seen that a shaft 62 is concentrically disposedwithin shaft 30 for rotation relative thereto. Bearings (not shown)spaced longitudinally of the shafts and disposed therebetween may beemployed to permit shaft 62 to rotate freely within shaft 30 with aminimum of friction. A thrust bearing 63 in housing 28 suspends shaft 62by its upper end.

A pinion 64 is rigid with the upper end of shaft 62. A pinion 66 isrigidly attached to the upper end of shaft 30, both of the pinions 64and 66 being in engagement with a ring gear 68. Ring gear 68 is mountedon output shaft 69 of prime mover 32, it being evident that mechanism.29 thus comprises a ring gear and pinion assembly for effectingrotation of shafts 30 and 62 in opposed directions upon actuation of theprime mover.

A bushing 70 in housing 28 permits longitudinal shifting of shaft 30 andpinion 66 while both of the shafts are being driven by the prime mover.It will be appreciated when the operation of the apparatus is describedhereinafter that such longitudinal shifting of shaft 30 is effected byoperation of crank 48 which, in turn, swings arm 34 about hinge 36.

The mixing structure proper of the instant invention comprises threeplates or discs 74, 76 and 78. Disc 74 is attached to shaft 30 by fourcurved legs 79 rigid with the lower end of the shaft. Disc 74 has aseries of apertures 80 therethrough in equally spaced relationship to acentral opening 82 in the disc communicating the opposed faces thereof.Rows of apertures 84 and 86 in progressively lesser spaced relationshipfrom central opening 82 are also provided in disc 74.

Four radial, inclined vanes 88 are attached to the upper side of disc 74and are canted toward the direction of rotation of the disc, suchrotation being effected by prime mover 32 in a manner to be describedhereinafter. Lower disc 78 is similar in construction to disc 74, thetwo discs being interconnected by four rods 90 which are rigid with anddepend from corresponding legs 79. Each rod 90 extends through anassociated hole 92 in disc 74 and is slidably received by acorresponding opening 93 in disc 78, a nut 95 being attached to thelower end of each rod to maintain disc 78 on the rods. A compressionspring 94 surrounds each rod 90 and bears against the opposed sides ofdiscs 74 and 78. The inner or middle disc 76 is held between discs 74and 78 in equally spaced relationship thereto by eight leaf springs 96mounted in corresponding recesses 98 in the upper and lower sides ofdisc 76. Four leaf springs 96 are mounted on each side of the disc as isclearly revealed in FIG. 4.

It may be seen that disc 76 has three continuous rows 100, 102 and 104of apertures therethrough. The rows 100, 102 and 104 are inprogressively lesser spaced relationship from a central, rectangularopening 106 in disc 76.

Reference is made particularly to FIGS. 2 and 7 for an understanding ofthe manner in which the discs 74, 76 and 78 are driven. Shaft 62 has atransversely circular section 108 and a transversely rectangular section110, the section 110 extending through opening 82 in disc 74 and intomating engagement with opening 106 in disc 76. Section 110 also extendsthrough a circular opening 112 in disc 78. The lower end of section 110is provided with a retainer or pressure plate 116 rigid therewith andabutting the underside of disc 78. The mating surfaces of disc 78 andretainer 116 form bearing surfaces and permit relative movement of disc78 and retainer 116 during operation of the mixing apparatus. Section110, therefore, is in driving engagement with disc 76 only.

In the operation of the apparatus, products to be mixed are loaded intothe receptacle 10 through inlet 14 and the inlet then closed by cap 16.Motor 32 is then energized, it being understood that the shafts 30 and62 are rotated in opposite directions. Thus, discs 74 and 78 are rotatedin one direction (counterclockwise looking vertically downwardly on theapparatus) while disc 76 is rotated in the other direction.

Since vanes 88 on the upper side of disc 74 are canted toward thedirection of rotation of the disc, the products to be mixed arecirculated downwardly through the rows of apertures 80, 84 and 86 andinto the interior of the disc mechanism between disc 74 and disc 76.Mixing and dispersion or comminution then occur because of the shearforces impressed upon the products by the relative movement of discs 74and 76. It may be appreciated that the rows 100, 102 and 104 ofapertures in disc 76 permit further passage of the products downwardlythrough the disc mechanism and into the space between discs 76 and 78,whereupon additional mixing occurs between these latter two discs.Continued circulation of the products results in flow thereof downwardlythrough apertures (not shown) in disc 78, the four radial vanes 114 onthe lower side'of disc '78 assisting in the establishment of a flowpattern from top to bottom through the disc mechanism. Deflector -17serves to restrict the circulation to the vicinity of the disc mechanismand prevents excessive upward flow of the products away from themechanism. It should be noted that, although shown and described as anintegral part of receptacle 10, deflector 17 may comprise a sleeve thatis inserted within the receptacle and adjustable toward and away fromthe mixing discs as desired.

Spacing between the discs is somewhat critical if the desired shearforces are to be produced within the disc mechanism. (The outer discsare shown in the drawings spaced from one another the maximum distance,i.e. disc 78 resting on nuts 95.) For this reason, arm 34 and itsassociated structure are provided to permit adjustment of the spacingbetween the discs. Rotation of crank 48 moves arm 34 toward and awayfrom top 12 and effects reciprocal movement of shaft 30. When shaft 30is moved downwardly, the legs 79 extending from shaft 30 force disc 74downwardly toward disc 78 against the action of springs 94 and 96 sincedisc 78 is maintained against downward movement by retainer 116.Conversetly, upward movement of shaft 30 permits discs 74 and 78 to moveaway from one another under the action of springs 94 and 96.

Attention is directed to the fact that, regardless of the distancebetween discs 74 and 78, disc 76 will always remain in equally spacedrelationship from the two outer discs. This is because of the action ofleaf springs 96 which serve to suspend or float disc 76 between discs 74and 78.

It should be understood that the coil springs 94 may be omitted from theadjusting mechanism and leaf springs 96 employed alone to effect theadjusting function. Furthermore, the leaf springs 96 may be omitted andthe coil springs 94 and associated rods replaced by spacer bars if noadjustment of the disc spacing is desired. The adjustable feature maynot be needed in certain grain comminuting applications. The spacingadjustment between the discs is important in most applications, however,since the magnitude of the shear forces impressed upon the productsbeing mixed is dependent upon this spacing. The closer the spacing, thegreater the shear and hence, the greater the heat developed in theproducts being mixed. Therefore, the spacing should be adjusted topermit maximum force on the products without overheating.

The spacing of the discs is especially important when substances such asthe constituents of paint are being mixed in the apparatus. Some degreeof heat is needed if the paint pigment is to be deglomerated andproperly mixed with the remainder of the ingredients, yet overheatingmust be avoided to prevent product damage. In this regard, receptaclemay be surrounded by a water jacket or other suitable means forpreventing overheating.

It has been found that optimum results are obtained when the aperturesin the discs comprise approximately 50% of the surface area thereof. Itshould be understood that these apertures assist in the generation ofthe shear forces, but with a sacrifice in circulation the apparatus isoperable with the disc apertures extending only partially through thediscs.

Although three discs are shown herein, additional discs may be added toor subtracted from the disc mechanism shown, depending on thecharacteristics of the substances being mixed and the efiiciency andspeed of operation desired. Furthermore, one disc or set of discs may bemaintained stationary, while the other disc or set thereof is rotated,and it is not requisite to the operability of this invention that thenonrotated disc or discs be provided with apertures therein.

Having thus described the invention, What is claimed as new and desiredto be secured by Letters Patent is:

1. Apparatus for mixing products comprising:

a receptacle for receiving said products;

an inner disc and a pair of outer discs in parallel, co-

axial relationship with one another, each of the discs having aplurality of apertures therethrough communicating opposed sides thereof;means mounting the discs in the receptacle for rotation of the outerdiscs as a unit in one direction about said axis and for rotation ofsaid inner disc in the other direction about said axis with the discsdisposed in sufliciently closely spaced relationship to one another tocause shear forces to be impressed upon said products when the discs arerotated; and

means operably coupled with said discs for driving the latter in saiddirections, whereby to produce said shear forces.

2. The invention of claim 1, wherein said inner disc is equally spacedfrom said outer discs.

3. The invention of claim 1, wherein said axis is substantiallyvertical, there being a product deflector in the receptacle above saiddiscs.

4. The invention of claim 1, wherein said axis is substantiallyvertical, there being a plurality of radial vanes 5. The invention ofclaim 1, wherein is provided a plurality of inclined, radial vanes onthe side of one of said outer discs remote from the inner dics, saidvanes being canted toward the direction of rotation of said one outerdisc.

6. The invention of claim 1, wherein said apertures in each of the discsreduce the surface area thereof approximately one-half.

7. Apparatus for mixing products comprising: a receptacle for receivingsaid products; an inner disc and a pair of outer discs in parallel, co-

axial, equally spaced relationship with one another, each of the discshaving a plurality of apertures therethrough communicating opposed sidesthereof;

yieldable means on the opposed sides of said inner disc in engagementwith the proximal sides of said outer discs for maintaining said equalspacing regardless of the distance between said outer discs;

structure mounting the discs in the receptacle for rotation of the outerdiscs in one direction about said axis and for rotation of the innerdisc in the opposite direction about said axis, said structure includinga reciprocable member operably coupled with one of the outer discs formoving the latter toward the other outer disc against the action of saidyieldable means and away from said other outer disc under the action ofthe yieldable means, whereby to vary said distance between the outerdiscs to change the magnitude of the shear forces impressed upon theproducts when the discs are rotated and means interconnecting said outerdiscs for relative movement thereof along said axis and for rotation asa unit about said axis; and

means operably coupled with said structure for driving the discs in saiddirections, whereby to produce said shear forces.

References Cited by the Examiner UNITED STATES PATENTS 897,481 9/1908Pease 259-24 1,655,447 1/1928 Wait 259-435 2,301,204 11/1942 Fields.2,626,135 1/1953 Serner 259134 X 2,734,728 2/1956 Meyers 24l161 XCHARLES A. WILLMUTH, Primary Examiner.

1. APPARATUS FOR MIXING PRODUCTS COMPRISING: A RECEPTACLE FOR RECEIVINGSAID PRODUCTS; AN INNER DISC AND A PAIR OF OUTER DISCS IN PARALLEL,COAXIAL RELATIONSHIP WITH ONE ANOTHER, EACH OF THE DISCS HAVING APLURALITY OF APERTURES THERETHROUGH COMMUNICATING OPPOSED SIDES THEREOF;MEANS MOUNTING THE DISCS IN THE RECEPTACLE FOR ROTATION OF THE OUTERDISCS AS A UNIT IN ONE DIRECTION ABOUT SAID AXIS AND FOR ROTATION OFSAID INNER DISC IN THE OTHER DIRECTION ABOUT SAID AXIS WITH THE DISCSDISPOSED IN SUFFICIENTLY CLOSELY SPACED RELATIONSHIP